US3789127A - Arc furnaces - Google Patents

Arc furnaces Download PDF

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Publication number
US3789127A
US3789127A US00321273A US3789127DA US3789127A US 3789127 A US3789127 A US 3789127A US 00321273 A US00321273 A US 00321273A US 3789127D A US3789127D A US 3789127DA US 3789127 A US3789127 A US 3789127A
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United States
Prior art keywords
vessel
electrodes
electrode
source
charge
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Expired - Lifetime
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US00321273A
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English (en)
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B Bowman
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British Steel Corp
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British Steel Corp
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Publication date
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Publication of US3789127A publication Critical patent/US3789127A/en
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B7/00—Heating by electric discharge
    • H05B7/02—Details
    • H05B7/06—Electrodes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D3/00—Charging; Discharging; Manipulation of charge
    • F27D3/18—Charging particulate material using a fluid carrier
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B7/00—Heating by electric discharge
    • H05B7/005—Electrical diagrams
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B7/00—Heating by electric discharge
    • H05B7/02—Details

Definitions

  • An electric arc furnace adapted to be powered by direct current includes a bottom electrode of one polarity (positive) mounted in the vessel for contact with the charge and three electrodes of negative polarity depending into the vessel from above.
  • the arcs from the electrodes migrate inwardly which is the opposite of the case with ac. thus reducing erosion of the furnace walls by concentrating the heat source in the centre.
  • the bottom electrode design is such as to enable the furnace to be tapped whilst maintaining a reservoir of metal for the succeeding charge.
  • ARC FURNACES This invention relates to are furnaces and more particularly relates to d.c. arc furnaces for refining metal e.g., melting and refining steel scrap.
  • the present invention comprises a direct-arc furnace adapted to be powered by direct current and including at least one electrode of one polarity mounted in the refining vessel for contact with the charge and a plurality of electrodes of the opposite polarity dependent into the vessel above the charge.
  • the latter electrodes are symmetrically disposed around a circular path concentric with the vessel walls and are all connected to the negative source of polarity, functioning as cathodes.
  • the vessel electrode (anode) may be constituted by a reservoir of the metal refined located in the base or hearth of the vessel with an elongated fillet or plug extending from it for contact with the positive source of supply. During melting or refining the reservoir will melt but contact with the bus bar will always be maintained through the solid/liquid interface thus formed in this electrode.
  • the disposition and design of the vessel electrode is such that the molten reservoir is not completely evacuated during tapping so that the necessary contact is available for the succeeding charge.
  • a d.c powered arc furnace in accordance with this invention results in a more stable and uniform arc than is the case with ac. since the dependent electrodes operate continuously as cathodes and not alternately as cathode and anode, accordingly consumption of the (graphite) electrodes is-less. Operation is also quieter than with ac furnaces of comparable rating. More sig nificant however is the reduction in erosion of the refractory lined walls of the furnace by reason of the arcs from the multiple electrodes migrating inwardly towards the centre of the furnace instead of migrating outwardly towards the walls as is the case with ac. Thus substantial savings in operating costs may be achieved.
  • the power supply for the furnace is derived from a star/deltaconnected transformer 5, the secondary windings of which separately apply an appropriate phase to fullwave rectifier banks 6,7,8 comprising silicon rectifiers.
  • FIG. 2a shows the electrodes disposed above the molten bath (13) in elevation from which it can be seen that the slag 14 on the surface of the melt is to a large degree blown to the centre of the furnace e.g., away from the refractory lining on the furnace walls thus reducing hot spot erosion arising from radiation/convection from the flames and/or slag at tack.
  • This is illustrated in plan in FIG. 2b, the appropriate lobes of power dissipation by the arcs being identified by numerals 15,16 and 17.
  • the three electrodes are symmetrically arranged around a circle concentric with the walls of the furnace and, as compared with ac operation, the pitch circle diameter on which these electrodes lie is preferably greater than the ac. case in order to ensure that scrap will be adequately melted off the banks adjacent the walls of the vessel.
  • the vessel (positive) electrode is sited in its base or hearth and provides a liquid/solid steel connection.
  • the electrode is constituted by a steel reservoir 18 and a fillet or elongated plug 19 the extremity of which is water-cooled, contained in a specially designed receptacle 20 in the base.
  • This may in fact be a castable refractory, it being understood that in a practical furnace the whole of this base protrusion could well be housed in refractory brickwork.
  • common bus bar 9 is secured to the remote end of a leg 21 of this receptacle 20.
  • the plug a solid steel member, is preformed with the electrode itself, e.g., by a casting process, and machined to ensure good contact with the bus bar.
  • the leg 21 extends in the same direction as the bus bar and the furnace tilts about an axis substantially parallel with these members.
  • a multiphase rectified supply for each electrode would be preferable to the single-phase system shown but against this multiphase rectifiers tend to introduce harmonics into the supply.
  • a direct arc furnace comprising:
  • a refining vessel for receiving a steelmaking charge
  • At least one electrode mounted in the vessel for contact with the charge
  • the electrodes being symmetrically arranged around a circular path about the vertical axis of the vessel;
  • a furnace according to claim 2, wherein the vessel electrode is constituted by a reservoir of the refined steel located in a well in the base or hearth of the vessel, and including an enclosed rod of metal extending from the reservoir for connection to the positive supply of the d.c. source.
  • a furnace according to claim 4 wherein the rod lies in a direction parallel with the axis about which the furnace is tilted.
  • a furnace according to claim 5, wherein said d.c. source is constituted by a multi-phase rectifier bank whereby to provide a multi-phase rectified supply for each electrode.
  • a direct arc furnace comprising:
  • a refining vessel for receiving a steelmaking charge
  • At least one electrode mounted in the vessel for contact with the charge
  • said one electrode means for connecting said one electrode to the positive supply of the d.c. source and wherein said one electrode is constituted by a reservoir of the refined steel located in a bowlshaped depression in the wall or hearth of the-vessel whereby, when the vessel is tilted for tapping,

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
  • Furnace Details (AREA)
  • Discharge Heating (AREA)
US00321273A 1972-01-18 1973-01-05 Arc furnaces Expired - Lifetime US3789127A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB242172A GB1398881A (en) 1972-01-18 1972-01-18 Direct arc furnaces

Publications (1)

Publication Number Publication Date
US3789127A true US3789127A (en) 1974-01-29

Family

ID=9739274

Family Applications (1)

Application Number Title Priority Date Filing Date
US00321273A Expired - Lifetime US3789127A (en) 1972-01-18 1973-01-05 Arc furnaces

Country Status (8)

Country Link
US (1) US3789127A (ja)
JP (1) JPS5624186B2 (ja)
BE (1) BE794174A (ja)
DE (1) DE2300341A1 (ja)
FR (1) FR2168430B1 (ja)
GB (1) GB1398881A (ja)
IT (1) IT977610B (ja)
SE (1) SE395105B (ja)

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3940551A (en) * 1973-03-30 1976-02-24 Allmanna Svenska Elektriska Aktiebolaget Apparatus and method for the melt reduction of iron oxides
US3949151A (en) * 1974-03-12 1976-04-06 British Steel Corporation Arc furnaces
US3988525A (en) * 1974-05-21 1976-10-26 Allmanna Svenska Elektriska Aktiebolaget Direct current arc furnace with charging means
US3997712A (en) * 1974-06-19 1976-12-14 Allmanna Svenska Elektriska Aktiebolaget Electric arc furnace
US4079185A (en) * 1975-04-02 1978-03-14 Asea Aktiebolag Method and apparatus for the melt reduction of iron oxides
US4461010A (en) * 1982-07-29 1984-07-17 Electro-Petroleum, Inc. Power supply circuit for a direct current arc furnace
US4468782A (en) * 1981-06-09 1984-08-28 Asea Aktiebolag Method and device for operating a DC arc furnace
US4586188A (en) * 1983-03-08 1986-04-29 Bbc Brown, Boveri & Co., Ltd. Apparatus for converting a three-phase arc furnace to d.c. operation
US5138630A (en) * 1989-11-06 1992-08-11 Nkk Corporation Direct current electric arc furnace
US5410564A (en) * 1990-03-19 1995-04-25 Kawasaki Steel Corporation Direct current electric furnace for melting metal
US5666891A (en) * 1995-02-02 1997-09-16 Battelle Memorial Institute ARC plasma-melter electro conversion system for waste treatment and resource recovery
US5756957A (en) * 1995-02-02 1998-05-26 Integrated Environmental Technologies, Llc Tunable molten oxide pool assisted plasma-melter vitrification systems
US6018471A (en) * 1995-02-02 2000-01-25 Integrated Environmental Technologies Methods and apparatus for treating waste
US6066825A (en) * 1995-02-02 2000-05-23 Integrated Environmental Technologies, Llc Methods and apparatus for low NOx emissions during the production of electricity from waste treatment systems
US6466605B1 (en) * 2000-06-20 2002-10-15 Electro-Pyrolysis, Inc. Concentric electrode DC arc system and their use in processing waste materials
CN106211409A (zh) * 2016-08-30 2016-12-07 三门峡强芯铸造材料有限公司 一种新型冶炼短网

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE7605217L (sv) * 1976-05-07 1977-11-08 Asea Ab Smeltkontaktelektrod
JPS59109769A (ja) * 1981-06-09 1984-06-25 アセア・アクチ−ボラグ 直流ア−ク炉の操業方法と炉床接続装置
DE3141312A1 (de) * 1981-10-17 1983-07-07 Leybold-Heraeus GmbH, 5000 Köln Vakuumlichtbogen-schmelz- und -giessofen mit vakuumkammer und kipptiegel
GB2111772B (en) * 1981-12-10 1985-09-18 Tioxide Group Plc Electric arc discharge apparatus
EP0207929A1 (de) * 1985-06-17 1987-01-07 VOEST-ALPINE Aktiengesellschaft Elektroofen, insbesondere Plasmaofen
FR2588432B1 (fr) * 1985-10-04 1987-11-27 Jeumont Schneider Dispositif d'alimentation en courant continu d'au moins deux charges electriques ayant une polarite commune, en particulier pour l'alimentation d'arcs electriques multiples
JPH0346192U (ja) * 1990-09-14 1991-04-26

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2448886A (en) * 1945-05-19 1948-09-07 Kellogg M W Co Electric furnace
US2789152A (en) * 1955-06-01 1957-04-16 Nat Res Corp Electric furnace for production of metals
US2789150A (en) * 1955-05-25 1957-04-16 Nat Res Corp Heat reservoir and electrode for production of metals in skull type furnace
US3180916A (en) * 1961-04-28 1965-04-27 Pechiney Prod Chimiques Sa Electric arc furnaces and method

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2448886A (en) * 1945-05-19 1948-09-07 Kellogg M W Co Electric furnace
US2789150A (en) * 1955-05-25 1957-04-16 Nat Res Corp Heat reservoir and electrode for production of metals in skull type furnace
US2789152A (en) * 1955-06-01 1957-04-16 Nat Res Corp Electric furnace for production of metals
US3180916A (en) * 1961-04-28 1965-04-27 Pechiney Prod Chimiques Sa Electric arc furnaces and method

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3940551A (en) * 1973-03-30 1976-02-24 Allmanna Svenska Elektriska Aktiebolaget Apparatus and method for the melt reduction of iron oxides
US3949151A (en) * 1974-03-12 1976-04-06 British Steel Corporation Arc furnaces
US3988525A (en) * 1974-05-21 1976-10-26 Allmanna Svenska Elektriska Aktiebolaget Direct current arc furnace with charging means
US3997712A (en) * 1974-06-19 1976-12-14 Allmanna Svenska Elektriska Aktiebolaget Electric arc furnace
US4079185A (en) * 1975-04-02 1978-03-14 Asea Aktiebolag Method and apparatus for the melt reduction of iron oxides
US4468782A (en) * 1981-06-09 1984-08-28 Asea Aktiebolag Method and device for operating a DC arc furnace
US4461010A (en) * 1982-07-29 1984-07-17 Electro-Petroleum, Inc. Power supply circuit for a direct current arc furnace
US4586188A (en) * 1983-03-08 1986-04-29 Bbc Brown, Boveri & Co., Ltd. Apparatus for converting a three-phase arc furnace to d.c. operation
US5138630A (en) * 1989-11-06 1992-08-11 Nkk Corporation Direct current electric arc furnace
US5410564A (en) * 1990-03-19 1995-04-25 Kawasaki Steel Corporation Direct current electric furnace for melting metal
US5798497A (en) * 1995-02-02 1998-08-25 Battelle Memorial Institute Tunable, self-powered integrated arc plasma-melter vitrification system for waste treatment and resource recovery
US6066825A (en) * 1995-02-02 2000-05-23 Integrated Environmental Technologies, Llc Methods and apparatus for low NOx emissions during the production of electricity from waste treatment systems
US5666891A (en) * 1995-02-02 1997-09-16 Battelle Memorial Institute ARC plasma-melter electro conversion system for waste treatment and resource recovery
US5811752A (en) * 1995-02-02 1998-09-22 Integrated Environmental Technologies, Llc Enhanced tunable plasma-melter vitrification systems
US5908564A (en) * 1995-02-02 1999-06-01 Battelle Memorial Institute Tunable, self-powered arc plasma-melter electro conversion system for waste treatment and resource recovery
US6018471A (en) * 1995-02-02 2000-01-25 Integrated Environmental Technologies Methods and apparatus for treating waste
US6037560A (en) * 1995-02-02 2000-03-14 Integrated Environmental Technologies, Llc Enhanced tunable plasma-melter vitrification systems
US5756957A (en) * 1995-02-02 1998-05-26 Integrated Environmental Technologies, Llc Tunable molten oxide pool assisted plasma-melter vitrification systems
US6127645A (en) * 1995-02-02 2000-10-03 Battelle Memorial Institute Tunable, self-powered arc plasma-melter electro conversion system for waste treatment and resource recovery
US6160238A (en) * 1995-02-02 2000-12-12 Integrated Environmental Technologies, Inc. Tunable molten oxide pool assisted plasma-melter vitrification systems
US6215678B1 (en) 1995-02-02 2001-04-10 Integrated Environmental Technologies, Llc Arc plasma-joule heated melter system for waste treatment and resource recovery
US6630113B1 (en) 1995-02-02 2003-10-07 Integrated Environmental Technologies, Llc Methods and apparatus for treating waste
US6466605B1 (en) * 2000-06-20 2002-10-15 Electro-Pyrolysis, Inc. Concentric electrode DC arc system and their use in processing waste materials
CN106211409A (zh) * 2016-08-30 2016-12-07 三门峡强芯铸造材料有限公司 一种新型冶炼短网

Also Published As

Publication number Publication date
FR2168430B1 (ja) 1978-12-29
JPS4881708A (ja) 1973-11-01
FR2168430A1 (ja) 1973-08-31
DE2300341A1 (de) 1973-07-26
BE794174A (fr) 1973-05-16
SE395105B (sv) 1977-07-25
JPS5624186B2 (ja) 1981-06-04
IT977610B (it) 1974-09-20
GB1398881A (en) 1975-06-25

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